CNC Dan
Veteran Member
What do you mean by grinding the start and back stepping on the welds? ?
Sorry but ain't %100 sure what you mean
Grinding the starts/stops is done because that's where the weld is often bad. If you stop welding, then re-start the weld, you have a start and a stop in the same place. Twice as bad. With MIG you may have a cold strart, and when stopping, you may lose gas coverage while the puddle is hot. With stick, you may not have the rod up to tempature right away at the start, and at the end, you might leave an unfilled crater.
Grinding away where the weld stoped gets rid of the bad part, and striking the arc for the re-start ahead of the tie in point will let the rod (stick welding) get up to temperature before you start making the bead. This will reduce the possibility of having defects in the weld.